At the very beginning, Ian intended to control the Body of the Dark Gold Gigantic Dragon to head directly to Dragon Bone Plaza, take the Divine Marrow and Dragon Crystal, and then leave.
In all endeavors, the strategic objective is paramount: as long as Ian obtains the Scorching Suspended Star Dragon's Divine Marrow and Dragon Crystal, along with a portion of the Source of Dragon Blood, he can repair the Dragon Heart Core within his body and possess a second Fifth Energy Level to construct the 'Divine Marrow of the Dragon' along with the relevant operational system.
By then, as long as he reaches the pinnacle of the Fourth Level, achieving Fifth Energy Level would come naturally!
But the problem is, plans never keep up with changes.